Control valve accelerated degradation experiment method

Abstract

The invention discloses a control valve accelerated degradation experiment method which comprises the following steps: S1, determining a control valve fault mode according to real working conditions; s2, sorting fault modes of the control valve, and carrying out degradation mechanism analysis; s3, accelerated stress selection and experiment setting; and based on degradation mechanism analysis, determining experiment schemes corresponding to different fault modes. The method comprises the following steps: firstly, according to a real working condition, determining a fault mode which is easy to occur on the control valve under the condition, namely finding out a fault mode with relatively high occurrence frequency; secondly, on the basis of the sorted fault modes, degradation mechanism analysis is carried out on the fault modes, and the degradation mode of the fault is determined according to the mechanism; and finally, based on an analyzed degradation mechanism, selecting a key index which can best represent performance degradation of the control valve in the fault mode, determining acceleration stress according to the key index, and finally determining a specific method for accelerated degradation of the control valve fault by analyzing and clearing the index, thereby collecting more process data in a short time.

Description

Technical Field

[0001] The present invention relates to the technical field of pneumatic control valve fault diagnosis, and more particularly to a control valve accelerated degradation test method. Background Art

[0002] Control valves are essential components in modern industrial automation control systems, widely used in fields such as petrochemicals, electric power, metallurgy, and natural gas. They precisely control fluid flow, pressure, and temperature, and their stability and reliability directly impact the safety and efficiency of production processes. Therefore, with control valve failures leading to serious consequences such as production line downtime, equipment damage, and even accidents, timely identification and accurate location of control valve failures has become a key issue in the industrial automation field.

[0003] Currently, there are three main approaches to control valve fault diagnosis: model-based diagnosis, data-driven diagnosis, and a fusion of model and data-driven diagnosis. Thanks to advances in artificial intelligence and enhanced computing power, data-driven methods have become the mainstream approach to control valve fault diagnosis. Data-driven methods avoid the need to develop complex dynamic models and only require high-quality, reliable fault data to accurately diagnose control valve faults.

[0004] Data-driven methods require high-quality data. However, for control valves, the probability of failure of control valves operating normally in a factory is extremely small. Therefore, this leads to difficulties such as difficulty in obtaining control valve failure samples and small data volume. To address these difficulties, the current mainstream method is to obtain a large amount of data under experimental conditions by adopting a fault reproduction method. That is, under experimental conditions, by simulating real working conditions and performing some "destructive" operations on the control valve, the control valve is close to or even reaches the real fault condition, and the data under the fault condition is collected as training data for subsequent diagnostic models.

[0005] The above methods for reproducing control valve failures all involve direct operations on the control valve itself. For example, valve core sedimentation failures are often caused by disassembling the control valve body and the actuator, inserting wire, iron filings and other foreign objects into the valve seat to limit the stroke of the control valve, or directly adding a limit device to the valve stem for simulation. This simulation method is simple and can obtain a large amount of data in a short period of time, but it ignores one point. In reality, control valve failures are gradual, that is, failures gradually develop from shallow to deep during normal operation, and most failures are not sudden.

[0006] Therefore, in order to effectively characterize the changing process of control valve failure and make fault diagnosis more accurate, it is necessary to collect the failure process data of the control valve. At this time, it is necessary to conduct accelerated degradation experiments on the control valve. By increasing the stress, the control valve failure is more likely to occur in a short time, thereby providing a large amount of process data for fault diagnosis at low cost and high reliability. Summary of the Invention

[0007] In view of this, the present invention provides a control valve accelerated degradation test method, through which the control valve failure can be gradually caused under real working conditions, that is, the failure changes from shallow to deep, so that the failure simulation using this method will be closer to the real evolution of the failure, and the control valve failure process data is collected to provide high-quality and reliable process data for the subsequent diagnosis model training, thereby realizing timely judgment and accurate positioning of the control valve failure.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A control valve accelerated degradation test method comprises the following steps:

[0010] S1. Determine the control valve failure mode based on actual operating conditions;

[0011] S2. Sort out the control valve failure mode and analyze the degradation mechanism;

[0012] S3. Accelerated stress selection and experimental setup: Based on degradation mechanism analysis, determine the experimental scheme corresponding to different failure modes.

[0013] The beneficial effects of the technical solution of the present invention are as follows: first, the existing failure modes of the control valve are sorted out, and based on the actual working conditions, the failure modes that are prone to occur in the control valve under these conditions are determined, that is, the failure modes that occur more frequently are found; secondly, based on the sorted out failure modes, the degradation mechanism of these failure modes is analyzed, and the degradation mode of the failure (such as plastic deformation, material damage, etc.) is determined based on the mechanism; finally, based on the analyzed degradation mechanism, the key indicators that can best characterize the performance degradation of the control valve under this failure mode are selected, and the accelerated stress is determined based on this, including: stress type and stress magnitude. By analyzing the above indicators clearly, the specific method of accelerated degradation of the control valve failure can be finally determined, and more process data can be collected in a short time.

[0014] Preferably, in step S1 , the control valve failure modes determined include valve core and valve seat failure, spring aging, and diaphragm wear.

[0015] Preferably, in step S2, the valve core failure degradation mechanism is the valve position tracking error caused by particle accumulation and material corrosion; the valve seat failure degradation mechanism is the valve position tracking error caused by particle accumulation and material corrosion; the spring aging degradation mechanism is the mechanical fatigue caused by the long-term use of the valve, which leads to a decrease in the spring stiffness coefficient; the diaphragm wear degradation mechanism is the uneven force caused by the tilt of the spring, which leads to wear on one side, or wear caused by excessive use due to material aging.

[0016] Preferably, in step S3, the valve core failure or valve seat failure test scheme:

[0017] Add metal chips and gravel to the fluid medium container and set the degradation plan:

[0018] Set the impurity concentration to 5% and adjust the pipeline pressure until the flow rate is reduced to 50% of the original;

[0019] Set the impurity concentration to 10% and adjust the pipeline pressure until the flow rate is reduced to 30% of the original;

[0020] The observation time is once every two hours, and data is collected at the same time. Step tests are performed to increase the valve core switching frequency and accelerate the mechanical interaction between the deposits and the valve core surface.

[0021] Preferably, in step S3, the spring aging test scheme is:

[0022] Set the pressure of the pressure reducing valve to 0.65Mp and adjust the valve core action frequency to 0.5HZ, that is, once every 5s;

[0023] Set the pressure of the pressure reducing valve to 0.75Mp and adjust the valve core action frequency to 1HZ, that is, once per second;

[0024] The valve was actuated using a step test, with observations every two hours while data was collected.

[0025] Preferably, in step S3, the diaphragm wear test scheme is:

[0026] Add small particles of gravel to the inside of the actuator and the edge of the diaphragm;

[0027] Set the pressure of the pressure reducing valve to 0.55Mp, add particles with a particle size of 0.5cm, and adjust the valve core action frequency to 0.2HZ, that is, once every 5s;

[0028] Set the pressure of the pressure reducing valve to 0.7 MPa, add particles with a diameter of 1 cm, and adjust the valve core action frequency to 0.5 Hz, i.e., once every 2 seconds;

[0029] The valve was actuated using a step test, with observations every two hours while data was collected.

[0030] Preferably, in step S1, under normal operating conditions, the medium in the fluid pipeline will continuously flow through the valve core and valve seat of the control valve, and the fluid medium will flush the valve core and valve seat for a long time, which will cause impurities in the medium to slowly deposit or adhere to the valve core or valve seat, thereby causing valve core and valve seat precipitation failure; the spring and gas inside the pneumatic actuator will provide force to drive the valve core to move, and long-term driving of the valve will cause mechanical fatigue of the spring, thereby causing spring aging failure; due to the continuous movement of the spring, the diaphragm inside the pneumatic actuator is continuously worn under the long-term action of the spring force, causing diaphragm wear failure.

[0031] It can be seen from the above technical solution that, compared with the prior art, the present invention provides a control valve accelerated degradation test method, which has the following beneficial effects:

[0032] 1. Accelerated degradation testing is consistent with the evolution of control valve failures under actual conditions: Faults reproduced using the accelerated degradation test method are more consistent with the evolution of failures under real working conditions. Traditional reproduction methods can only record the final state of the failure and lack quantitative data on the degradation process. Accelerated degradation testing achieves continuous monitoring of control valve performance by increasing the stress level and captures the gradual evolution of the failure.

[0033] 2. Reduced time cost: Relying on fault reproduction under natural usage conditions, the experimental time is limited by the product's service life, and the occurrence of failures takes a long time. The accelerated degradation method accelerates the degradation process of materials or structures by increasing stress, which greatly shortens the time it takes for failures to occur compared to traditional reproduction methods.

[0034] 3. The degradation mechanism is more reliable: The traditional fault reproduction method is to perform "destructive" operations directly on the control valve. If the operation is not done properly, it may cause the injection of new failure modes. The accelerated degradation method ensures the consistency of the degradation mechanism with the actual operation process by analyzing the failure mode of each fault. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0036] Figure 1 This is a flow chart of the accelerated degradation experiment provided by the present invention. DETAILED DESCRIPTION

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0038] The embodiment of the present invention discloses a control valve accelerated degradation test method, comprising the following steps:

[0039] S1. Determine the control valve failure mode based on actual operating conditions;

[0040] Under normal working conditions, the medium in the fluid pipeline will continuously flow through the valve core and valve seat of the control valve, and the factory's production efficiency is improved by increasing the medium flow rate. The fluid medium will flush the valve core and valve seat for a long time, which will cause impurities in the medium to slowly deposit or adhere to the valve core or valve seat, thereby causing valve core and valve seat sedimentation failure, which is also the most common failure mode under factory conditions.

[0041] Secondly, the control valve needs to receive centralized control instructions based on different media flows to adjust the opening and closing degree of the valve. The spring and gas inside the pneumatic actuator provide the force to drive the valve core. Driving the valve for a long time will cause mechanical fatigue of the spring, thus causing spring aging failure.

[0042] Finally, due to the continuous movement of the spring, the diaphragm inside the pneumatic actuator is constantly worn under the long-term action of the spring force, causing diaphragm wear failure;

[0043] S2. Sort out the control valve failure mode and analyze the degradation mechanism;

[0044] The analysis in step S1 revealed four common failure modes: valve core and valve seat sedimentation or corrosion, spring aging, and diaphragm wear.

[0045] Valve core precipitation and corrosion degradation mechanism: impurities in the medium slowly adhere to the valve core surface or corrosive media flushes the valve core for a long time, causing rust on the valve core surface;

[0046] Degradation mode: particle accumulation, material corrosion;

[0047] Fault phenomenon: reflected in the deviation between the actual valve position value and the valve position setting value;

[0048] Key performance indicators: valve position tracking error;

[0049] Valve seat precipitation and corrosion degradation mechanism: the phenomenon of impurities in the medium slowly depositing and hindering the movement of the valve stem, or the corrosive medium eroding the valve seat for a long time, causing rust on the valve seat surface;

[0050] Degradation mode: particle accumulation, material corrosion;

[0051] Fault phenomenon: reflected in the deviation between the actual valve position value and the valve position setting value;

[0052] Key performance indicators: valve position tracking error;

[0053] Spring aging degradation mechanism: Long-term use of the valve causes the spring stiffness coefficient to decrease;

[0054] Degradation mode: mechanical fatigue;

[0055] Fault phenomenon: The valve position may not reach the set value, with a large deviation and a large overshoot;

[0056] Key performance indicators: valve position tracking error, overshoot;

[0057] Diaphragm wear and degradation mechanism: uneven force due to spring tilt causes wear on one side or wear caused by long-term use;

[0058] Degradation mode: material aging;

[0059] Fault phenomenon: The valve position cannot be stabilized at the set value and is accompanied by a large overshoot.

[0060] Key performance indicators: valve position tracking error, overshoot;

[0061] S3. Accelerated stress selection and experimental setup: Based on degradation mechanism analysis, determine the experimental scheme corresponding to different failure modes.

[0062] Valve core and valve seat precipitation failure mode:

[0063] Experimental conditions:

[0064] Fluid medium: pure water;

[0065] Pipeline working pressure: lower than normal working pressure, in order to reduce the flow rate;

[0066] Impurity additives: metal debris, sand and gravel;

[0067] The specific plan is as follows:

[0068] Add metal chips and gravel to the fluid medium container. According to the volume of the container, set the following two degradation schemes:

[0069] A. Set the impurity concentration to 5% and adjust the pipeline pressure until the flow rate is reduced to 50% of the original;

[0070] B. Set the impurity concentration to 10% and adjust the pipeline pressure until the flow rate is reduced to 30% of the original;

[0071] The observation time is once every two hours, and data is collected at this time. During this period, a step test is performed to increase the valve core switching frequency and accelerate the mechanical interaction between the deposits and the valve core / seat surface;

[0072] Valve core and valve seat corrosion failure mode:

[0073] The specific solution for corrosion failure is the same as that for precipitation failure mentioned above, but the experimental conditions need to be changed to acidic corrosive medium and impurities and additives need to be removed.

[0074] Spring aging failure mode:

[0075] Experimental conditions:

[0076] Fluid medium: pure water;

[0077] Pipeline working pressure: normal working pressure;

[0078] Accelerated stress: mechanical load;

[0079] Impurity additives: None;

[0080] The specific plan is as follows:

[0081] A. Set the pressure of the pressure reducing valve to 0.65Mp (depending on the actual spring preload), and adjust the valve core action frequency to 0.5HZ, i.e. once every 5s;

[0082] B. Set the pressure of the pressure reducing valve to 0.75Mp and adjust the valve core action frequency to 1HZ, that is, once per second;

[0083] The valve is driven by a step test, and the observation time is once every two hours, and the data at this time is collected simultaneously;

[0084] Diaphragm wear failure mode:

[0085] Experimental conditions:

[0086] Fluid medium: pure water;

[0087] Pipeline working pressure: normal working pressure;

[0088] Accelerated stress: mechanical load;

[0089] Impurity additives: sand and gravel;

[0090] The specific plan is as follows:

[0091] Add small sand particles to the edge of the diaphragm inside the actuator and adopt the following two solutions:

[0092] A. Set the pressure of the pressure reducing valve to 0.55 MPa (depending on the actual spring preload), add particles with a diameter of 0.5 cm, and adjust the valve core action frequency to 0.2 Hz, i.e., once every 5 seconds.

[0093] B. Set the pressure of the pressure reducing valve to 0.7 MPa, add particles with a diameter of 1 cm, and adjust the valve core action frequency to 0.5 Hz, i.e., once every 2 seconds;

[0094] The valve is driven by a step test, and the observation time is once every two hours, and the data at this time is collected simultaneously.

[0095] In order to further optimize the above technical solution, when conducting the diaphragm wear accelerated degradation experiment, first, the top cover of the pneumatic actuator is disassembled using the corresponding tools. The spring and diaphragm can be seen inside. Particles with a particle size of 0.5 cm are added to the edge of the diaphragm (that is, the place where the actuator top cover bolts are fastened). The particles can be gravel, metal chips, etc., and then the top cover is screwed back to the actuator to restore the control valve to its original rotation state; then, the pressure of the pressure reducing valve is adjusted to be about 20% higher than the normal operating pressure of the actuator, and the action frequency of the valve core is changed by changing the period of the input current signal.

[0096] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0097] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A control valve accelerated degradation test method, characterized in that: The following steps are involved: S1. Determine the control valve failure mode based on actual operating conditions; S2. Sort out the control valve failure mode and analyze the degradation mechanism; S3. Accelerated stress selection and experimental setup: Based on degradation mechanism analysis, determine the experimental scheme corresponding to different failure modes.

2. A control valve accelerated degradation test method according to claim 1, characterized in that: In step S1 , the control valve failure modes determined include valve core and valve seat failure, spring aging, and diaphragm wear.

3. A control valve accelerated degradation test method according to claim 2, characterized in that: In step S2, the valve core failure degradation mechanism is the valve position tracking error caused by particle accumulation and material corrosion; the valve seat failure degradation mechanism is the valve position tracking error caused by particle accumulation and material corrosion; the spring aging degradation mechanism is the mechanical fatigue caused by the long-term use of the valve, which leads to the decrease of the spring stiffness coefficient; the diaphragm wear degradation mechanism is the uneven force caused by the tilt of the spring, which leads to wear on one side, or the wear caused by excessive use due to material aging.

4. A control valve accelerated degradation test method according to claim 3, characterized in that: In step S3, valve core failure or valve seat failure test plan: Add metal chips and gravel to the fluid medium container and set the degradation plan: Set the impurity concentration to 5% and adjust the pipeline pressure until the flow rate is reduced to 50% of the original; Set the impurity concentration to 10% and adjust the pipeline pressure until the flow rate is reduced to 30% of the original; The observation time is once every two hours, and data is collected at the same time. Step tests are performed to increase the valve core switching frequency and accelerate the mechanical interaction between the deposits and the valve core surface.

5. The control valve accelerated degradation test method according to claim 3, characterized in that: In step S3, spring aging experimental plan: Set the pressure of the pressure reducing valve to 0.65Mp and adjust the valve core action frequency to 0.5HZ, that is, once every 5s; Set the pressure of the pressure reducing valve to 0.75Mp and adjust the valve core action frequency to 1HZ, that is, once per second; The valve was actuated using a step test, with observations every two hours while data was collected.

6. The control valve accelerated degradation test method according to claim 3, characterized in that: In step S3, the diaphragm wear experimental plan: Add small particles of gravel to the inside of the actuator and the edge of the diaphragm; Set the pressure of the pressure reducing valve to 0.55Mp, add particles with a particle size of 0.5cm, and adjust the valve core action frequency to 0.2HZ, that is, once every 5s; Set the pressure of the pressure reducing valve to 0.7 MPa, add particles with a diameter of 1 cm, and adjust the valve core action frequency to 0.5 Hz, i.e., once every 2 seconds; The valve was actuated using a step test, with observations every two hours while data was collected.

7. The control valve accelerated degradation test method according to claim 1, characterized in that: In step S1, under normal operating conditions, the medium in the fluid pipeline will continuously flow through the valve core and valve seat of the control valve. The fluid medium will flush the valve core and valve seat for a long time, which will cause impurities in the medium to slowly deposit or adhere to the valve core or valve seat, thereby causing valve core and valve seat precipitation failure; the spring and gas inside the pneumatic actuator will provide the force to drive the valve core to move. Long-term driving of the valve will cause mechanical fatigue of the spring, thereby causing spring aging failure; due to the continuous movement of the spring, the diaphragm inside the pneumatic actuator is continuously worn under the long-term action of the spring force, causing diaphragm wear failure.

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